BBC security correspondent Gordon Corera said immediate suspicion about Monday's attack would fall on militants from the Caucasus region.

Militant groups fighting in the Caucasus know how important the perception that the president and prime minister provide a secure society is, and to undermine that is a key aspect of their aims, adds our correspondent.

Last March the Russian capital's underground system was rocked by two female suicide bombers from Russia's volatile Dagestan region, who detonated their explosives on the busy metro system during rush hour, killing 40 people and injuring more than 80.

No mention of suspected Islamic militants. No mention of the worldwide jihad. No mention of the desire of those "militant groups" to establish a caliphate.

As for motivations behind those who are responsible, all that the BBC can manage to unearth is that

President Dmitry Medvedev has admitted that poverty, corruption and conflict in the North Caucasus is Russia's biggest internal problem.

Ya, that and maybe the blinders being worn by British journalists and Russian leaders alike.